Abstract:

During the growth process, peanut plants are often subject to various biological stresses such as aphids, spider mites, Aspergillus flavus, and Aspergillusniger. Avoiding or reducing the damage caused by these pests and diseases is one of the important issues in the development of peanut plants. Endophytic bacteria can not only promote the growth of peanut plants but also enhance their resistance to pests and diseases. This study explored the effect of YMR3, an endophytic bacterium isolated from the roots of Yueyou 7, on the resistance of peanut plants to several pests and diseases. The results showed that spraying peanut leaves at the four-leaf stage with YMR3 bacterial solution at OD600nm 0.8 effectively reduced the damage caused by aphids and spider mites. Injecting the same concentration of YMR3 bacterial solution into the top leaves of peanut plants at the four-leaf stage effectively reduced the damage caused by A. flavus and A.niger to peanut plants or leaves. Further research found that inoculating YMR3 increased the expression of AhRS1 (the key synthesis enzyme gene for resveratrol) and the activity of the AhRS1 promoter in peanut leaves, as well as increased the content of resveratrol in peanut leaves. External application of 100 μg/mL resveratrol also significantly reduced the proportion of leaf spots caused by A. flavus. These results indicate that YMR3 may regulate the expression of AhRS1 inpeanut leaves by regulating the activity of the AhRS1 promoter, increase the content of resveratrol in peanut leaves to respond to the damage caused by A. flavus, and reduce the damage caused by aphids, spider mites, A. niger, and A. flavus to peanut leaves. The research results provide a theoretical basis for the development of YMR3 as a biological pesticide.

Key words:

peanut endophyte, strain YMR3, resistance to pest and disease stress, resveratrol